Tora-jirushi Kongo-do No.80

Artificial stone, substitute for Ara-to.
1st stone of the groundwork, used before Binsui-do.
Kongo-do is used when the sword has rust or flaw.
We have several types of Kongo-do, so please choose the one according to the condition of the sword.
No.80 is used especially when the sword is rusted heavily.